Reverse shoulder prosthetic

ABSTRACT

A reverse modular humeral implant for implantation into a humerus that includes a natural humeral shaft and a natural humeral head. The implant includes a humeral stem implantable into the natural humeral shaft, and an adapter couplable to the humeral stem, the adapter including an anchoring projection configured to be coupled to a convex bearing.

FIELD

The present disclosure relates to a humeral prosthesis for totalshoulder joint replacement and generally includes a prosthetic humeralstem, a bearing coupling mechanism, and a prosthetic head which replacesa portion of the humeral joint.

BACKGROUND

This section provides background information related to the presentdisclosure which is not necessarily prior art.

It is not uncommon for the exterior surface of the humeral head to bedamaged or defective. Conventionally, a variety of humeral headresurfacing implants exist for repairing humeral head surfaces. Whileconventional humeral head resurfacing implants are suitable for theirintended uses, such implants are subject to improvement.

Conventional humeral implants fail to accommodate patients havinginadequate skeletal structure needed during a revision procedure.Specifically, conventional implants do not permit articulation betweenthe implant and the concave undersurface of the coracoacromial arch ofthe scapula, the coracoacromial arch being a structural component of theshoulder comprising the coracoacromial ligament, coracoid process, andacromion. Thus, there is a need for a humeral implant that permitsrevision of the articulation surface to allow proper articulationdynamics.

SUMMARY

This section provides a general summary of the disclosure, and is not acomprehensive disclosure of its full scope or all of its features.Various aspects of the teachings provide a modular humeral implant andassociated kit and method for implantation into a humerus that includesa natural humeral shaft and a natural humeral head.

A modular reverse shoulder prosthetic for a revision procedure istaught. The reverse shoulder prosthetic can have a glenoid trayconfigured to be implanted into a resected glenoid. The tray can have anopposed bearing mounting surface defining a coupling aperture therein.The aperture has a first portion with a first internal diameter and asecond portion with a second internal diameter, the second internaldiameter being larger than the first diameter, wherein the first portioncan be disposed between the second portion and the bearing mountingsurface and wherein a locking surface can be defined at an interfacebetween the first and second portions. A bearing coupling member isprovided which is configured to engage the bearing mounting surface, thebearing coupling member can have a coupling flange extending generallyperpendicular therefrom. The flange can have a depending locking memberconfigured to be disposed through the first portion and into the secondportion of the coupling aperture and to engage the locking surface. Themounting portion having a bearing coupling side can have a couplingtaper configured to mate to a corresponding taper on a bearing member.

According to alternate teachings, the shoulder prosthetic can have aglenoid tray configured to be implanted into the resected glenoid. Thetray can have a glenoid interface surface with a depending coupling stemand an opposed bearing mounting surface. The bearing mounting surfacedefines a coupling aperture therein. The coupling aperture can have afirst portion with a first internal diameter and a second portion with asecond internal diameter. The second internal diameter can be largerthan the first diameter, and the first portion can be disposed betweenthe second portion and the bearing mounting surface. A locking surfacecan be defined at the interface between the first and second portions.The bushing member is first disposed within the glenoid tray, anddefines an aperture having a plurality of generally planar bearingsurfaces defining a bushing member bearing ledge. A bearing couplingmember is disposed within the bushing member.

The bushing member can have a planar interface surface configured toengage the bearing mounting surface. The bearing mounting surface canhave a coupling flange extending generally perpendicular therefrom. Abearing coupling member can be disposed therein. The bearing couplingmember can have a bearing coupling side having a coupling surfaceconfigured to mate to a corresponding surface on a bearing member.

According to alternate teachings, the bearing coupling member can definea bearing coupling member coupling ledge configured to slidably engagethe bushing member bearing ledge when the bearing coupling member isengaged with the bushing and the glenoid tray. The bearing couplingmember is translatable with respect to the bushing.

Further areas of applicability of the present invention will becomeapparent from the detailed description provided hereinafter. It shouldbe understood that the detailed description and specific examples, whileindicating the preferred embodiment of the invention, are intended forpurposes of illustration only and are not intended to limit the scope ofthe invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings described herein are for illustrative purposes only ofselected embodiments and not all possible implementations, and are notintended to limit the scope of the present disclosure.

FIG. 1 is a view of a humeral implant according to the prior art;

FIG. 2 is an exploded view of a reverse humeral implant according to thepresent teachings;

FIGS. 3 a-3 c are end views of the coupling member, bushing, and trayaccording to the present teachings;

FIGS. 4 a-4 d are side exploded views of a humeral implant subassemblyusing the coupling mechanism, bushing, and tray according to the presentteachings;

FIG. 5 is an assembled end view of the coupling mechanism and trayaccording to the present teachings in an engaged position; and

FIGS. 6-9 represent cross-sectional views of a revision procedure.

DETAILED DESCRIPTION

Example embodiments will now be described more fully with reference tothe accompanying drawings.

FIG. 1 represents a shoulder prosthetic system according to the priorart. Shown is a coupling, bearing or glenoid tray 20 having a dependentstem 21 and fixation edge 22. Disposed within the glenoid tray 20 is apolymer glenoid 23 having a mounting interface 24 and concave bearingsurface 25. The concave bearing surface 25 is configured to interfacewith the articulating surface of a humeral prosthetic 26. Generally, theconcave bearing surface 25 is configured to interface with a humeralprosthetic.

The humeral prosthetic has a stem 27 which can be coupled to themedullary canal of a resected humerus 28. Alternatively, a short stemhead prosthetic can be used. As further described below, the prostheticsystem can at least be partially removed in a revision procedure. FIG. 2represents an exploded perspective view of the reverse shoulder system29 according to the present teachings. The reverse shoulder system 29utilizes the glenoid tray 20 to couple a reverse shoulder head member 30to the prepared glenoid after a traditional glenoid member has beenremoved in a revision procedure.

As described below, the head member 30 is coupled to the glenoid tray 20using an intermediary or bearing coupling member 31. Disposed about thebearing coupling member 31 is a polymer sleeve, bushing member orbushing 32, which can be coupled to the bearing coupling member 31 andthe glenoid tray 20. The bearing coupling member 31 is non-rotatablyfastened to the glenoid tray 20 using a fastener 35. In this regard, thebearing coupling member 31 has a generally cylindrical coupling flange37 which is inserted into a bore 36 defined within the glenoid tray 20.The bushing 32 engages the fixation edge 22 to prevent rotation of thebearing coupling member 31.

The fastener 35 can be used to fixably couple the bearing couplingmember 31 to the glenoid tray 20. The polymer bushing 32 defines aninterior coupling bore 41 defining at least one flat bearing surface 39.Optionally, the interior coupling bore 41 can define four interceptingflat bearing surfaces which form a square or a rectangle. The interiorcoupling bore 41 radially supports the bearing coupling member 31 on apair of parallel sides. As described below, the bearing coupling member31 is slid along the axis 42 of the interior coupling bore 41 to movethe locking member or coupling flange 37 from an unengaged to an engagedposition.

FIGS. 3 a-3 c represent end views of the glenoid tray 20 and associatedbushing 32. Shown are snapped ends 46 which rotationally lock both theglenoid bearing or bushing into the glenoid tray 20. As best seen inFIGS. 3 a and 4, the glenoid tray 20 defines a central coupling bore 47.The coupling bore 47 has a first portion 49 having a first diameter, anda second portion 50 having a second diameter. The second portion 50defines a locking surface 51 configured to interface with a couplingflange of the bearing coupling member 31.

FIGS. 4 a-4 d represent exploded views of alternate mechanisms forcoupling the bearing coupling member 31 to the glenoid tray 20. Whilesimilar, each coupling mechanism has different advantages. As shown inFIGS. 4 a and 4 b, the bearing coupling member 31 can be coupled throughthe interior coupling bore 41 defined in the bushing 32. The couplingflange 37 can take the form of a cylinder or coupling taper.Additionally, the fastener 35 can be used to couple the bearing couplingmember 31 to the glenoid tray 20.

As shown in FIGS. 4 c and 4 d, the bearing coupling member 31 can becoupled through the interior coupling bore 41 defined in the bushing 32and into the first and second portion of the bore 36. The couplingflange 37 takes the form of a cylinder coupling flange. The couplingflange 37 has a depending flange 52 configured to interface with thelocking surface 51. The coupling flange 37 is centered at a locationgenerally offset on a first side from the centerline of the bearingcoupling member 31. The bearing coupling member 31 defines a throughbore38 generally offset on a second opposed side from the centerline of thebearing coupling member 31. The fastener 35 can be passed through thethroughbore 38 and at least partially into the first portion of thecoupling bore to couple the bearing coupling member 31 to the glenoidtray 20.

As best seen in FIG. 5, the coupling mechanism depending flange 52 isconfigured to interface with the locking surface 51. The flange 52 isconfigured to fit through the smaller diameter first portion 49 of thecoupling bore 47. It, therefore, has a cross-sectional area and geometrywhich allows its transfer from a first non-engaged position to anengaged position after the depending flange is passed through into thesecond portion 50. This engagement releasably locks the bearing couplingmember 31 to the glenoid tray 20. The addition of the fastener throughthe offset throughbore 38 locks the coupling member in place. It isenvisioned the coupling member can have either male or female lockingtapers or an exterior coupling taper 43 to couple the head member 30 tothe glenoid tray 20.

FIGS. 6-8 depict side exploded views of a procedure to couple theinterface coupling system to the glenoid tray 20. In this regard, it isenvisioned that the glenoid tray 20 could have been previously coupledto the glenoid in a traditional arthroplasty (see FIG. 1). FIG. 6depicts the glenoid tray 20 coupled to a prepared glenoid. Shown is thecentral coupling bore 47 with associated first and second portions 49and 50.

As shown in FIG. 7, after the bushing 32 is coupled to the glenoid tray20, the bearing coupling member 31 is positioned though the bushingcoupling aperture or bore 41 in contact with a bearing surface of theglenoid tray 20. Defined about the external periphery of the bearingcoupling member 31 can be a cutout or ledge portion configured tointerface with a ledge defined within the bushing coupling aperture orbore 41.

The coupling flange 37 has an exterior surface having a generally fixedradius of curvature about the centerline defining the body. The couplingflange 37 generally can present a one-half cylinder which has across-sectional area smaller than the cross-sectional area of thecoupling bore 47 in the glenoid tray 20. The flange extended ledgeportion 52 extends generally perpendicular to a centerline defining theextending ledge portion 52. As shown in FIGS. 7 and 8, the ledge portion52 is configured to interface with the locking surface 51.

The reverse shoulder prosthetic can have a glenoid tray 20 configured tobe implanted into a resected glenoid. The glenoid tray 20 can have aglenoid interface surface 60 and an opposed bearing mounting surface 61.The bearing coupling member 31 can have a planar interface surface 63configured to engage the bearing mounting surface 61.

Shown in FIG. 8, the bushing 32 defines bushing bore 41 having aplurality of generally planar bearing surfaces which define a bushingmember bearing ledge 68. The bearing coupling member 31, disposed withinthe bushing 32, has a planar interface surface 69 configured to engagethe bearing mounting surface 61. The bearing coupling member can betranslated with respect to the glenoid tray 20. The bearing couplingmember 31 can be translatable with respect to the glenoid tray 20 froman unlocked position to a locked position. The bearing coupling member31 is translatable with respect to the glenoid tray in a directionparallel to the bearing mounting surface from a first unlocked position(FIG. 7) to a second locked position (FIG. 8).

As best seen in FIG. 9, a head 30 can be coupled to the exteriorcoupling taper 43 formed on the bearing coupling member 31. It isenvisioned that the interfering ledges can hold the bushing 32 in placeagainst the glenoid tray 20 and the bushing 32 inhibits rotation of thebearing coupling member 31.

Example embodiments are provided so that this disclosure will bethorough, and will fully convey the scope to those who are skilled inthe art. Numerous specific details are set forth such as examples ofspecific components, devices, and methods, to provide a thoroughunderstanding of embodiments of the present disclosure. It will beapparent to those skilled in the art that specific details need not beemployed, that example embodiments may be embodied in many differentforms and that neither should be construed to limit the scope of thedisclosure. In some example embodiments, well-known processes,well-known device structures, and well-known technologies are notdescribed in detail.

The terminology used herein is for the purpose of describing particularexample embodiments only and is not intended to be limiting. As usedherein, the singular forms “a”, “an” and “the” may be intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. The terms “comprises,” “comprising,” “including,” and“having,” are inclusive and therefore specify the presence of statedfeatures, integers, steps, operations, elements, and/or components, butdo not preclude the presence or addition of one or more other features,integers, steps, operations, elements, components, and/or groupsthereof. The method steps, processes, and operations described hereinare not to be construed as necessarily requiring their performance inthe particular order discussed or illustrated, unless specificallyidentified as an order of performance. It is also to be understood thatadditional or alternative steps may be employed.

When an element or layer is referred to as being “on”, “engaged to”,“connected to” or “coupled to” another element or layer, it may bedirectly on, engaged, connected or coupled to the other element orlayer, or intervening elements or layers may be present. In contrast,when an element is referred to as being “directly on,” “directly engagedto”, “directly connected to” or “directly coupled to” another element orlayer, there may be no intervening elements or layers present. Otherwords used to describe the relationship between elements should beinterpreted in a like fashion (e.g., “between” versus “directlybetween,” “adjacent” versus “directly adjacent,” etc.). As used herein,the term “and/or” includes any and all combinations of one or more ofthe associated listed items.

Although the terms first, second, third, etc. may be used herein todescribe various elements, components, regions, layers and/or sections,these elements, components, regions, layers and/or sections should notbe limited by these terms. These terms may be only used to distinguishone element, component, region, layer or section from another region,layer or section. Terms such as “first,” “second,” and other numericalterms when used herein do not imply a sequence or order unless clearlyindicated by the context. Thus, a first element, component, region,layer or section discussed below could be termed a second element,component, region, layer or section without departing from the teachingsof the example embodiments.

Spatially relative terms, such as “inner,” “outer,” “beneath”, “below”,“lower”, “above”, “upper” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. Spatiallyrelative terms may be intended to encompass different orientations ofthe device in use or operation in addition to the orientation depictedin the figures. For example, if the device in the figures is turnedover, elements described as “below” or “beneath” other elements orfeatures would then be oriented “above” the other elements or features.Thus, the example term “below” can encompass both an orientation ofabove and below. The device may be otherwise oriented (rotated 90degrees or at other orientations) and the spatially relative descriptorsused herein interpreted accordingly.

The foregoing description of the embodiments has been provided forpurposes of illustration and description. It is not intended to beexhaustive or to limit the invention. Individual elements or features ofa particular embodiment are generally not limited to that particularembodiment, but, where applicable, are interchangeable and can be usedin a selected embodiment, even if not specifically shown or described.The same may also be varied in many ways. Such variations are not to beregarded as a departure from the invention, and all such modificationsare intended to be included within the scope of the invention.

What is claimed is:
 1. A prosthetic comprising: a glenosphere definingan articulating surface; a glenoid tray defining an interior couplingbore having a planar locking surface; a bushing member disposed withinthe glenoid tray, the bushing member defining an aperture having aplurality of generally planar bearing surfaces and forming a bushingmember bearing ledge; and a bearing coupling member disposed within thebushing member, the bearing coupling member having a planar interfacesurface configured to engage the bushing member bearing ledge, theplanar interface surface having a coupling flange extending generallyperpendicular therefrom, the coupling flange having a depending lockingmember configured to be disposed through the interior coupling bore andto engage the planar locking surface, the bearing coupling member havinga bearing coupling side having a coupling member surface configured tomate to a corresponding glenoid coupling surface on the glenosphere. 2.The prosthetic according to claim 1, wherein the glenosphere has aspherical convex surface configured to interface with a concave bearing.3. The prosthetic according to claim 1, wherein the glenoid trayinterior coupling bore has a first portion with a first internaldiameter and a second portion with a second internal diameter, thesecond internal diameter being larger than the first internal diameter.4. The prosthetic according to claim 1, wherein the glenospherecomprises an extended articulating surface.
 5. The prosthetic accordingto claim 1, wherein the bearing coupling member is translatable withrespect to the bushing member.
 6. The prosthetic according to claim 1,wherein the bearing coupling member is translatable with respect to aglenoid in a direction parallel to the planar interface surface.
 7. Theprosthetic according to claim 1, wherein the bearing coupling member istranslatable with respect to the glenoid tray from a first unlockedposition to a second locked position.
 8. A shoulder prostheticcomprising: a glenoid tray configured to be implanted into a resectedglenoid, the glenoid tray having a glenoid interface surface having adepending coupling stem, the glenoid tray having an opposed bearingmounting surface, the opposed bearing mounting surface having a bearingengagement member and defining an interior coupling bore therein, theinterior coupling bore having a first portion with a first internaldiameter and a second portion with a second internal diameter, thesecond internal diameter being larger than the first internal diameter,wherein the first portion is disposed between the second portion and theopposed bearing mounting surface, and wherein a locking surface isdefined at an interface between the first portion and second portion; abushing member disposed within the glenoid tray, the bushing memberdefining an aperture having a plurality of generally planar bearingsurfaces defining a bushing member bearing ledge; and a bearing couplingmember disposed within the bushing member, the bearing coupling memberhaving a planar interface surface configured to engage the bushingmember bearing ledge, the planar interface surface having a couplingflange extending generally perpendicular therefrom, the coupling flangehaving a depending locking member configured to be disposed through thefirst portion and into the second portion of the interior coupling boreand to engage the locking surface, the bearing coupling member having acoupling taper configured to mate to a corresponding taper on a bearingmember.
 9. The shoulder prosthetic according to claim 8, wherein theplanar interface surface is configured to slidably engage the bushingmember bearing ledge when the bearing coupling member is engaged withthe bushing member and the glenoid tray.
 10. The shoulder prostheticaccording to claim 9, wherein the bearing coupling member istranslatable with respect to the glenoid tray from a first unlockedposition to a second locked position.
 11. The shoulder prostheticaccording to claim 8, wherein the bearing coupling member istranslatable with respect to the bushing member.
 12. The shoulderprosthetic according to claim 8, wherein the bearing coupling member istranslatable with respect to the glenoid tray.
 13. The shoulderprosthetic according to claim 8, wherein the opposed bearing mountingsurface is planar, and wherein the bearing coupling member istranslatable with respect to the glenoid tray in a direction parallel tothe opposed bearing mounting surface from an unlocked position to alocked position.
 14. A shoulder prosthetic comprising: a glenoid trayconfigured to be implanted into a resected glenoid, the glenoid trayhaving a glenoid interface surface and an opposed bearing mountingsurface, the opposed bearing mounting surface defining an interiorcoupling bore therein, the interior coupling bore having a first portionwith a first internal diameter and a second portion with a secondinternal diameter, the second internal diameter being larger than thefirst internal diameter, wherein said first portion is disposed betweenthe second portion and the opposed bearing mounting surface and whereina locking surface is defined at an interface between the first portionand second portion; a bearing coupling member having a planar interfacesurface configured to engage the opposed bearing mounting surface, theplanar interface surface having a coupling flange extending generallyperpendicular therefrom, the coupling flange having a depending lockingmember configured to be disposed through the first portion and into thesecond portion of the interior coupling bore and to engage the lockingsurface, the bearing coupling member having a bearing coupling sidehaving a coupling taper configured to mate to a corresponding taper on abearing member; and a bushing member disposed about the bearing couplingmember, the bushing member defining an inner bore having a plurality ofplanar bore surfaces, and wherein the bearing coupling member defines aplurality of coupling bearing planar surfaces configured to interfacewith the plurality of planar bore surfaces when the bearing couplingmember is engaged with the glenoid tray.
 15. The shoulder prostheticaccording to claim 1, wherein the coupling bearing member istranslatable with respect to the bushing member.
 16. The shoulderprosthetic according to claim 1, wherein the bearing coupling member istranslatable with respect to the glenoid tray.
 17. The shoulderprosthetic according to claim 1, wherein the bearing coupling member istranslatable with respect to the glenoid tray from a first unlockedposition to a second locked position.
 18. The shoulder prostheticaccording to claim 1, wherein the opposed bearing mounting surface isplanar, and wherein the bearing coupling member is translatable withrespect to the glenoid tray in a direction parallel to the opposedbearing mounting surface from a first unlocked position to a secondlocked position.